Airplane



NOV. 3, 1931. DAVIS 1,830,019

. AIRPLANE Filed May 6, 1931 3 Sheets-Sheet l NOV. 3, 1 931. H DAVIS I 1,830,019

AIRPLANE Filed May 6, 1931 3 Sheets-Sheet 2 INVENTOR.

Q E A121) HDr-wrs ATTORNEY.

E. H. DAVIS Nov. 3, 1931.

AIRPLANE Filed May 6, 1931 3 Sheets-Sheet 3 I N VEN TOR. WAIQD HDAVI s A TTORN E Y.

Patented Nov. 3, 1931- EDWARD. H. DAVIS, 01" CINCINNATI, OHIO mam Application filed Kay 6,

My invention relates to an airplane wing or, as technically termed airfoil and more especially to means in the form of a hlnged flap carried by said airfoil and mounted 1n 5 close proximity to its leading edge for varying the lift of said airfoil The general objectsof my invention are to provide means for varying the lift of an airplane airfoil, which means is simple, ef-

ficient, economical to manufacture, the numberof parts being reduced to a minimum and designed in such manner that it is fully reliable and automatic in its'operation, which is strong and at the same time light enough so that its added weight doesnot materially increase the stalling speed of the airplane upon which it is mountc It has alread been attempted to produce a device for de aying stall and maintaining 20 lateral control, such devices being known for years to those skilled in the art of alrcraft construction under the title slotted wings. This principle has been given scores of variations and applied to ailerons, as well as .to

airfoils but none of such means has given satisfaction, some being too complicated and expensive-to manufacture and others hardly practical, of short life or inadequate fully to satisfy the requirements.

The problem of producing a fully reliable and automatically operated mechanism for varying the lift of airfoils has been solved satisfactorily in the flap forming the subject of the present invention. The flap of the invention is characterized in that it is closed by air pressure during high speed and automatically opened at speeds that would normally represent a stall, without requiring the attention of the pilot in anv manner whatso- 0 ever.

My invention consists in providing a pivoted or hinged flap 'in close proximity to the leading edge of an airfoil and having its rear portion cut away to permit an air flow between said flap and airfoil when the flap 1931. Serial No. 585,482.

is in spaced apart relation relative to said air foil or in a position hereinafter referred to as the open position.

My invention also consists in the provision of means for pivotally mounting said flap in such a manner that there are substantially no 7 a1r res1st1ng projecting constructions to tend to impede the progress of the plane in either open or closed sition and when said flap is in closed position upon the airfoil a stream- -line effect is produced.

My invention further consists in so pivotally mounting the flap that when it movesupon its p1vot to open position the movement is fan-like upwardly instead of forward and produces an offset between the leading edge of the airfoil and the leading edge of the flap whereby the air is readily directed through the air passage and deflected along the upper surface of the airfoil to lift the same, as indicated by the arrows in Figs. 3 and 10.

My invention further consists in certain combmatlons, constructions and arrangement of parts which will be hereinafter described and specifically claimed.

In the accompanying drawings which for a part of this specification:

Fig. 1 is a plan view of a monoplane embodying myimproved hinged flaps upon the airfoil and shown also upon the tail surface or stabilizer; i

Fig. 2 is a similar view showing a modified form of the invention;

Fig. 3 is a horizontal section through the position and illustrating a modified construction;

Fig. 10 is a similar view showing the flap in operative or open position;

Fig. 11 is an enlarged fragmentary view of Fig. 9, partly in section, to show the flap operating mechanism; and

Fig. 12 is an end view of Fig. 11.

Referring to Fig. 1 of the drawings, 1 indicates the usual airfoil of an airplane designated 2, 3 the leading edge and 1 the trailing edge of said airfoil 1, 5 the tail surface or stabilizer and 66 the hinged flaps, the construction, location and arrangement of which constitute the present invention.

It will be noted, upon examination of Figs. 1 and 2, that I have illustrated two'diflerent constructions, that shown in Fig. 1 being adaptable for airfoils using solid beams of wood or similar construction, and the construction shown in Fig. 2 being adapted to airplanes having open beams or spars, such as steel tubes or I-beam construction. With these two forms, the design shown in Fig. 2 and in detail in Figs. 9 and 10, permits better streamlining than the construction shown in Fig. 1 and in detail in Figs. 3, 4 and 5, the principle of operation, however, being the same in both embodiments.

Referring first to the hinged flaps mounted upon airfoils having solid beams, attention is directed to Fig. 3, where the flap is seen in the open position. Since the flap is automatically opened up at low speeds, it will be understood that the normal position of the flap, when the plane is on the ground, is open.

In Fig. 1 I have shown two flaps 6 u on the airfoil 1, but if desired, they can e connected together or made as one flap and extend approximately the full length of the leading edge of saidairfoil, as shown in Fig. 2. However, the construction and operation of both flaps 6, shown in Fig.1, are identical and, therefore, the description of one will suffice for both.

Referring now to Fig. 3, the fla away at its rear between its nose 6 is cut and the pivot point 8, so as to provide a slot 9 between said flap 6 and upper surface of airfoil 1 when in the open position. The flap 6 is provided with integrally formed and rearwardly extending arms 10, which are pivotally attached at 8 to a supporting post 11, rigidly attached to the airfoil 1. The means for automatically opening or spacing the hinged flap 6 from the airfoil 1 comprises spring pressed arm 12, sleeve 13 of which is pivotally attached to bracket 14 by pin 15, said bracket being rigidly attached to the solid beam or spar 16 by screws 17, as clearly shown in Fig. 6. Tube 18 of spring pressed arm 12 is telescopically received within sleeve 13 and is provided with an eyemember 19 on its outer end which receives pin 20 carried by one of the integrally formed and-rearwardly extending arms 10, said pin being held therein by suitable means, as, for example, cotter-pin 21, shown in Fig. 6. Thus the eye-portion of tube 18 is pivotally attached to hinged flap 6, preferably through the medium of integrally formed arms 10.

Referring to Fig. 6, and again to Fig. 8, it will be clearly seen that sleeve 13 is provided with oppositely disposed elongated slots 22 within which the ends of pin 23 are adapted to slide under action of coil spring 24. One end of this spring 24 seats against head 25, carried within tube 18, and the other end against plug 26, screw-threaded within the outer end of sleeve 13, as clearly shown in Fig. 6.

hen the plane is on the ground or not in use the coil spring 24; forces tube 18 outwardly relative to sleeve 13, the outward movement being limited by the pin 23 engaging the outer end of the slots 22-22 in sleeve 13, thereby giving the eye-member 19 a c0rresponding movement due to its connection with tube 18 which, in turn, moves the pin 20 and the attached arm 10 of hinged flap 6 to thereby open the flap 6 to a position illustrated in Fig. 3. The tension of coil spring 24 is such that the flap 6 is held in the open position until a safe flying speed has been attained, at which time the air pressure overcomes the tension of the coil spring 24 and closes the flap 6 upon the airfoil 1, as shown in Fig. 4. The tension of the spring 24 can be quickly and conveniently changed so as to be increased or decreased by screwing the plug 26 farther within or out of the sleeve 13.

In Fig. 1 each of the flaps 6 is provided with two of such fiap operating means, the remaining arm or arms being merely pivoted at 8 to the airfoil 1 to help support the hinged flap. The number of sprin pressed arms needed for opening a hinged flap will depend entirely upon the size of airfoil under consideration which, in turn, determines the size of flap needed for eflicient operation.

Referring next to Figs. 9 and 10 the hinged flap construction used in connection with open beam airfoils will be explained: In Fig. 9 the flap 60; is shown in the closed position while in Fig. 10, said flap 6a is shown in the open position. This flap 60., shown in Fig. 2, extends substantially the entire length of the leading edge 3a of the airfoil 1a, as shown in Fig. 2, or can be divided into two separate flaps, as shown in Fig. 1, without materially affecting the principles of construction. The flap 6a, as shown in Fig. 2, is provided with a plurality of integrally attached and rearwardly extending arms 10a, which arms are pivotally attached at 8a to support post 11a in a manner similar to the arms 10 of flap 6. However, the major portions of these arms 10a are concealed within the airfoil 1a when the flap 6a is in the closed position, as shown in Fig. 9, and extend between tuhes or beams 16a of the open beam, as clearly illustrated. These arms 10a of the flap 6a, like the arms 10 of the flaps 6, are normally forced in a direction to open the flap Go by a spring pressed plunger 27,- the details of this plunger being clearly illustrated in Fig. 11.

An important advantage of my invention over prior patents, including my Patent No. 1,? 49,021, granted March 4, 1930, is the streamline eifect of the airfoil and flap when the latter is in closed position during high speed, thereby reducing to a minimum the resistance of the air against the plane, whereas in prior structures there are projections extending above the airfoil and flap at all times which come into contact with the air and tend to reduce the speed of the plane.

Gther advantages are simplicity of construction, there being only one'main moving part consisting of the flap itself; it is easy and economical to manufacture and is adapted to be readily attached to or removed from the airfoil by use of the hinge pins. 13% to the simple construction the weight of the flap and its attaching means is less than in other constructions and friction is reduced to a minimum, thereby producing greater freedom of action of the flap relative to the air pressure, it being more sensitive to varymg anpressures.

My invention is capable of modification without departure from the scope or spirit thereof as claimed.

What I claim as new and desire to secure by Letters Patent is:

1. In an airplane, an airfoil having a flap whose leading edge is located in front of the leading edge of the airfoil when said flap is in closed position, said flap having integrally formed arms extending through slots in I said airfoil and pivotally attached to said airfoil rearwardly of its leading edge, and means for automatically holding said flap in open position until overcome by the pressure of the air.

2. In an airplane, an airfoil having a flap whose leading edge is located in front of the leading edge of the airfoil when said flap is in closed position, said flap having integrally formed arms pivotally attached to said airfoil rearwardly of its leading edge and means for automatically holding said flap in open position until overcome by the pressure of the air.

3, in an airplane, an airfoil having a flap whose leadingedge is located in front of the leading edge of theairfoil when said flap is fied.

EDWARD H. DAVIS. 

